Typically, in a multi air-conditioning apparatus formed by connecting at least one heat source unit and a plurality of use units to each other by piping, construction workers carry out connection of refrigerant pipes and wire connection of transmission signal lines (transmission lines) on-site during installation work. The connection of refrigerant pipes and the wire connection of transmission lines are carried out individually; hence, there are cases in which a construction defect such as non-correspondence between a refrigerant pipe and a transmission line occur. Normally, a trial run is carried out after installation work; however, since all of the use units are operated during the trial run, even if there were a non-correspondence between a refrigerant pipe and a transmission line, the operation state will be the same as that when there is no non-correspondence. Accordingly, the non-correspondence between the refrigerant pipes and the transmission lines cannot be detected with the trial run, and there are cases in which a non-correspondence is found after the turn over to the user.
There has been proposed a technique automatically detecting such non-correspondence between the refrigerant pipes and the transmission lines.
For example, an air-conditioning apparatus described in Patent Literature 1 is a system in which each of a plurality of indoor units are connected to corresponding one of branch ports of branch units that have a plurality of electronic expansion valves. Patent Literature 1 discloses a method of detecting the correspondence between each pipe and each wiring of each indoor unit and the corresponding branching unit by making a plurality of indoor units all perform heating operation while each of the electronic expansion valves are dosed one by one.
Further, in an air-conditioning apparatus described in Patent Literature 2, diversion units each control diversion of a refrigerant to a plurality of indoor units. Patent Literature 2 discloses an air-conditioning apparatus that is capable of accurately recognizing the correspondence between each of the indoor units and the corresponding one of solenoid valves of the diversion units in a short time and that is capable of surely performing a desired cooling/heating operation of the indoor units by repeating an operation in which substantially half of the solenoid valves that is in an opened state is dosed and substantially half of the solenoid valves that is in a dosed state is opened for a number of times during trial run.